81157232 has 40 divisors (see below), whose sum is σ = 170145360. Its totient is φ = 37278720.

The previous prime is 81157229. The next prime is 81157261. The reversal of 81157232 is 23275118.

81157232 is nontrivially palindromic in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 81157195 and 81157204.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49319 + ... + 50937.

It is an arithmetic number, because the mean of its divisors is an integer number (4253634).

Almost surely, 2^81157232 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81157232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85072680).

81157232 is an abundant number, since it is smaller than the sum of its proper divisors (88988128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81157232 is a wasteful number, since it uses less digits than its factorization.

81157232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1881 (or 1875 counting only the distinct ones).

The product of its digits is 3360, while the sum is 29.

The square root of 81157232 is about 9008.7308762111. The cubic root of 81157232 is about 432.9546503681.

The spelling of 81157232 in words is "eighty-one million, one hundred fifty-seven thousand, two hundred thirty-two".